Transfer of data files to remote units through networks, such as the internet, puts large demands on processor capabilities, etc., when the files are large and the remote units are large in number. Specially, where data files are streamed individually to respective remote units, conventional storage and computation units, including hard drives, provides a limited capacity, and therefore the number of remote units that can be served with the use of such equipment is relatively low.
WO2008/028834 and WO2008/028835 disclose apparatuses for data streaming to a plurality of remote units, in which data files are pre-processed before being stored in a storage unit, whereby control data sets are created, and the data files being streamed using the control data sets, wherein a streaming unit receives from the storage unit, along with sub-sets of the data files, control data sub-sets, each giving a location in the storage unit of a further sub-set of the data file. This provides a possibility of obtaining a high performance with simultaneous data streaming to a very large number of remote units.
In certain communication protocols, such as the Transmission Control Protocol (TCP), two-way communication is included, at which messages, such as acknowledgements of received data, are sent in both directions between communicating units. There is a need to allow such two-way communication in cases of the type mentioned, where an apparatus sends simultaneously large data files to a large number of remote units, without large penalties on the performance of the apparatus.